• Economic and Environmental Geology
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• v.49 no.6
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• pp.445-458
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• 2016

Most of water curtain cultivation (WCC) area in Korea has been inveterately suffering from the gradual draw-down of groundwater level and related shortage of water resources at the late stage of WCC peak time. To solve this problem, artificial recharge techniques has been recently applied to some WCC area. This study introduces infiltration gallery, which is one of the artificial recharge methods, and tentatively examined the effectiveness of three galleries installed at Sangdae-ri WCC area of Cheongju City. Seven galleries are set up at each empty space between eight vinyl houses in this area and its dimension is designed as 50 cm in each width and height and 300 cm in each length. Installation process was including bed excavation, backfill with gravels and silica sands, and completion of gallery by equipment of piezometer and covering with non-woven cloth. For each B, C, D gallery, 3 types of test including preliminary, four step and one long-term injection were performed. The first preliminary test showed the rough relations between injection rates and water level rise as follows; 20 cm and 30 cm level rise for $33.29{\sim}33.84m^3/d$ and $45.60{\sim}46.99m^3/d$ in B gallery; 0 cm, 16 cm and 33 cm level rise for $21.1m^3/d$, $33.98m^3/d$ and $41.69m^3/d$ in C gallery; 29 cm and 42 cm level rise for $48.10m^3/d$ and $52.23m^3/d$ in D gallery. Afterwards, more quantitative results estimating effectiveness of artificial recharge were reasoned out through stepped and long-term injection tests, which is expected to be employed for estimating water quantity re-injected into the aquifer through these galleries by natural injection over the period of WCC peak time.

• Journal of the Korean Institute of Gas
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• v.1 no.1
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• pp.101-105
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• 1997

When the water curtain system is employed to keep the liquefied gas in the underground storage cavern, clogging is observed in borehole. Since this phenomenon causes serious difficulties in managing LPG storage cavern, it needs to detect the degree of clogging accurately under various circumstances. Thus, in this study the active factors of clogging, that is, groundwater head, injection water flowrate, and seepage water flowrate, were investigated experimentally using a physical model. Experimental results show that groundwater head around storage cavern increases as cavern Pressure increases, while it decreases as clogging becomes severe. The pressure in storage cavern is required to reduce up to atmospheric pressure in order to detect and identify the degree of clogging more accurately. The decrease of uroundwater head due to clogging slows down as the pressure in borehole increases. As amounts of suspended matters in injected water increase, both injection water flowrate and seepage water flowrate decrease linearly with time, and the flowrate of injection water drops rapidly compared with seepage water flowrate.

• Journal of Animal Environmental Science
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• v.7 no.1
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• pp.13-20
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• 2001

This study was conducted to investigate the actual conditions on housing and facilities for goat. This investigation of the actual conditions was investigated by the style of farm which was divided into sideline scale and speciality scale included 47 farms. The results are summarized as follows: Rearing scale was 48.9% for 50-100 heads per farm. Rearing type was 46.8% for grazing type and 53.2% for barn type. Housing type was 27.7% for simple frame housing and 72.3% for permanent housing. Pipe was used 80.8% with Pillar and Girder as the housing frame at farm. For the pipe used in farm, 27.7% of them was used for simple frame housing. Side wall was composed of cement and winch curtain to be 29.8%, slate roof to be 40.4%, pipe partition to be 38.3%, and cement floor to be 51.1%. Materials of feeding trough were wood and Zinc grater to be 41.5%, respectively. Type of feeding trough was square to be 70.2%. The feeding trough was located in barn to be 48.9%. Material of water supply facilities was plastic to be 87.2%. Type of water supply facilities was mostly square to be 76.6%. Water-trough was located in playground to be 48.9%. Parturition facilities were consisted of partition structure by group to be 42.5% and were mainly composed of pipe and wood. 46.8% of the barn did not have delivery room in the farm.

• The Korean Journal of Malacology
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• v.30 no.3
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• pp.273-279
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• 2014

The mass mortalities have been occurring of Korean scallop Patinopecten yessoensis from 1997's to now in Korea east sea. Cages behavior and interference effect (common name; curtain effect) between scallop cages were investigated in culture grounds on the eastern coastal waters of Korea for understand to mechanism of rising about mass mortalities of Korean scallop quickly. The first experiment was carried out in circulating water channel to assess inclination angel from relationship between velocity and cages interval, velocity with culture cages position. An angle of inclination of scallop culture cages were 94.6 to 92.3 degree under a several velocity which were from 0.1 m/s and 131.9 to 118.1 degree under 0.5 m/s with cages interval were 1 m, 94.3 to 91.0 degree under velocity is 0.1 m/s and 133.2 to 122.4 degree under 0.5 m/s with cages interval were 1.5 m and 94.6 to 96.4 degree under velocity is 0.1 m/s and 131.7 to 131.8 under 0.5 m/s with cages interval were 2 m. The second experiment was designed to prove the tank test. Velocities were measured inside and outside of the scallop culture ground at eastern sea of Korea. The velocity of inside of the culture was the slowest as 0.1m/s. In this result, interference between former cage and after cage was occurred.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.390-397
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• 2017

The introduction of exotic fish species may reduce the number of native fish species and disturb the aquatic ecosystem. Therefore, measures to block and manage fish species are required. Accordingly, a fish species blocking system using bubbles was developed in this study to block exotic fish species. An experimental channel was produced and the possibility of blocking such exotic fish species was evaluated. The bubble generator is a system that produces a bubble curtain by generating air with an air compressor that blocks fish species. Bluegill, which is an exotic fish species in the country, was tested with this generator. The size of bluegill was between 0.10 m and 0.15 m and the depth of water was maintained at 0.70 m. The flow velocity of the experiment channel was classified into 3 levels (0.20 m/s, 0.10 m/s, and 0.05 m/s) considering the natatorial ability of the fish species. The results revealed that 70.07% of bluegill showed movements to swim upstream before applying the bubble, but it is considered that the ascending rate would be higher given that the fish species thinks downstream is a habitat and showed almost no movement. However, when the blocking facility was installed, most fish species showed movements to return to the downstream again by the bubble curtain, indicating a very high blocking effect. In particular, when the generating bubble was terminated, the fish species swam back to the upstream area very soon, so the fish species blocking effect using the bubble was excellent.

• Journal of Soil and Groundwater Environment
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• v.16 no.6
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• pp.66-78
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• 2011

It is getting difficult to manage water resources in South Korea because more than half of annual precipitation is concentrated in the summer season and its intensity is increasing due to global warming and climate change. Artificial recharge schemes such as well recharge of surface water and roof-top rainwater harvesting can be a useful method to manage water resources in Korea. In this study, potential artificial recharge site is evaluated using geographic information system with hydrogeological and social factors. The hydrogeological factors include annual precipitation, geological classification based on geological map, specific capacity and depth to water level of national groundwater monitoring wells. These factors were selected to evaluate potential artificial recharge site because annual precipitation is closely related to source water availability for artificial recharge, geological features and specific capacity are related to injection capacity and depth to water is related to storage capacity of the subsurface medium. In addition to those hydrogeological factors, social aspect was taken into consideration by selecting the areas that is not serviced by national water works and have been suffered from drought. These factors are graded into five rates and integrated together in the GIS system resulting in spatial distribution of artificial recharge potential. Cheongsong, Yeongdeok in Gyeongsangbuk-do and Hadong in Gyeongsangnam-do, and Suncheon in Jeollanam-do were proven as favorable areas for applying artificial recharge schemes. Although the potential map for artificial recharge in South Korea developed in this study need to be improved by using other scientific factors such as evaporation and topographical features, and other social factors such as water-curtain cultivation area, hot spring resorts and industrial area where groundwater level is severely lowered, it can be used in a rough site-selection, preliminary and/or feasibility study for artificial recharge.

• Journal of Bio-Environment Control
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• v.25 no.4
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• pp.225-231
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• 2016

Glasshouse heating package technologies to improve energy usage efficiency in winter were developed. Heating package was composed of the ground water source heat pump with heating capacity of 105kW, the aluminum multi-layer thermal curtain with six layers of different materials and the root zone local heater with XL pipes of ${\phi}20mm$. Venlo type glasshouse($461m^2$) with the heating package was compared with the same type and area control glasshouse with the light oil boiler, the usual non-woven fabric thermal curtain with respect to the glasshouse inside temperature, relative humidity, crop growth, and heating energy consumption. The results of test in paprika cultivation glasshouses showed that the air temperature inside glasshouse with aluminum multi-layer thermal curtain was maintained $2.2^{\circ}C$ higher than that of control glasshouse in un-heating night time and the temperature in bed with root zone local heating was $4.7^{\circ}C$ higher than that in bed without local heating. Average heating coefficient of performance(COP) of the ground water source heat pump used in paprika cultivation was 3.7 and the glasshouse inside temperature was maintained at $21^{\circ}C$ of heating set up temperature. The heating energy consumptions per 10a were measured at 14,071L of light oil and 364kWh of electric power for the control glasshouse and 35,082kWh for the glasshouse applied heating package. As results, the heating cost of the glasshouse applied heating package was 87 percent lower than that of control glasshouse. The growths of paprika in glasshouses of control and applied heating package did not show any significant difference.

• The Journal of Engineering Geology
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• v.22 no.4
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• pp.387-398
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• 2012

Korean agricultural areas that employ water curtain cultivation (WCC) have recently suffered extensive groundwater shortages due to an increase in the number of facilities. The primary focus of this study is to measure the daily groundwater use and discharge rates in the Cheongweon and Chungju pilot areas, while the second focus is to estimate the total amount of groundwater used in WCC areas nationwide in Korea. Taking into consideration several factors, including motor type, outflow abilities of wells, records of daily minimum temperatures below $0^{\circ}C$, and the number of running wells according to weather variations, we estimated that $53,138m^3/ha$ of groundwater had been used in the 4-hectare Cheongweon pilot area during the winter period of late 2011 through early 2012. On a prorated areal basis, we can calculate that the total groundwater used nationwide was 0.57 billion $m^3$ in WCC areas of $10,746m^2$. This value is equivalent to 33.7% of the total agricultural groundwater use (1.69 billion $m^3$) in Korea. During 9-22 February 2012, the daily water discharge rate in the 4-ha Cheongweon pilot area ranged from 2,079 to $2,628m^3$, averaging $2,341m^3$. Combining this value with meteorological records for 94 days with a daily minimum temperature below $0^{\circ}C$ results in an estimated groundwater volume of $54,990m^3/ha$ for the pilot area during the 2011-2012 winter period. The total amount of groundwater used nationwide in WCC areas would then be 0.59 billion $m^3$, equivalent to 34.9% of the total agricultural groundwater use in Korea. In the Chungju area, the groundwater discharge rate was estimated to be less than 805 $m^3$/ha. This value, combined with weather data for 108 days with a daily minimum temperature below $0^{\circ}C$ in this area, can be applied to infer that the total groundwater volume used in WCC areas nationwide is no more than 55% of the total agricultural groundwater use in Korea.

• Journal of Bio-Environment Control
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• v.15 no.4
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• pp.306-316
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• 2006

In this study, the effect of the shade level, water flow rate applied to the shades and the temperature of water on the greenhouse cooling was investigated depending on the shade level of 0, 35, 55, 75%, and water flow rate and water temperature by the test on the small wooden frames to find out the low cost cooling method. With increasing of the dry bulb temperature of outside air, the dry bulb temperature in the wooden frames increased. For the frames with the shade and water, inside temperatures of the frames were lower of -0.2$\sim$-1.2$^{\circ}C$ than the temperature of the outside air and higher than the water temperature. For the frames without water, inside temperatures of the frames were higher of 1.7$\sim$4$^{\circ}C$ than the outside and not affected by the shade level very much. The water flow rate and the temperature of the water were not the important factors to decrease the inside temperatures in the frames. The black globe temperature became lower with increasing of shade level. The shade frames with water curtain showed the best cooling effect because of reducing thermal radiation and cooling the plastic film cover. The surface temperatures of the plastic film cover for the water supplied modules became lower with increasing of the shade level. The relative humidity was decreased with the dry bulb temperature in the frame increasing and not affected by the dry bulb temperature of the outside air for the frames with the shade and water.

• Journal of environmental and Sanitary engineering
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• v.18 no.3 s.49
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• pp.59-63
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• 2003

This study was carried out to get efficient of organic material removal and wastage sludge production minimized effects on the treatment of Brewhouse wastewater using aerobic RBC and curtain biological film contact process. As a results of biofilm attachment experiment aggravation of water quality due to excessive biofilm showed after every 13 days of operating times. The concentration of BOD at raw wastewater was 3800${\sim}$5300 mg/L and COD was 2300${\sim}$3100 mg/L. The average BOD of effluent was maintained 18 mg/L and average COD was 26 mg/L. The result of this experiment was wastage sludge did not almost generated.